Safety device for stair-climbing systems

ABSTRACT

A safety device for stairway elevator systems ( 10 ) used for transporting apparatus and goods, especially wheelchairs ( 9 ) with persons who are unable to walk. The device is characterized in that the stairway elevator ( 10 ) or wheelchair ( 9 ) is fitted with a mounting device ( 20 ) equipped with a rotation pin ( 21 ). A support bracket ( 30 ) is mounted on the rotation pin ( 21 ) and a braking and blocking device ( 40 ) is attached to both the support bracket ( 30 ) and mounting device ( 20 ). A sensor ( 70 ) controls the braking and blocking device ( 40 ) in such a way that it blocks the support bracket ( 30 ) as soon as the stairway elevator ( 10 ) is at risk of tipping over and down the stairs ( 1 ) and releases the support bracket ( 30 ) when the stairway elevator ( 10 ) is placed at a correct angle to the stairs( 1 ).

BACKGROUND OF THE INVENTION

The invention relates to safety devices to be used with stair-climbingsystems (also referred to as “stair-climbers”) for conveying equipmentand goods, in particular wheelchairs with handicapped persons.

Two construction principles are widely known for stair-climbers used forconveying wheelchairs with handicapped persons in stairways. Oneconstruction principle uses crawler chassis. The crawlers are longenough for at least three stairs to be grasped at the same time. In thisway, accidental tipping over of the wheelchair and the person isimpossible, so that falls with resulting injuries or even deaths areruled out. These stair-climbers have problems with narrow and curvedstairways, however, due to the length and width of the crawler chassis.

The other construction principle uses numerous wheels that rotate notonly around their own axle but at the same time around an axle shared byall wheels. Cf. DE-C 37 13 564 or DE-C 32 26 294. With theseapparatuses, it is advantageous on the one hand that only rubber-tiredwheels come into contact with the stairway and, in particular, the stairedge, in such a way that damage is largely ruled out; on the other hand,it is quite dangerous that the wheels can only engage the steps to alimited depth. Operating these devices therefore requires particularcaution and circumspection, namely not the least because the load is ahuman being. In actual fact, however, stairways have many differentdesigns: they range from relatively flat stairways running completelystraight to narrow, steep, winding staircases. Climbing the stairs withthe stair-climbers based on the multiple-wheel principle is not withoutdanger because the apparatus can tilt. The stair-climber, the wheelchairand the person must therefore be held by a strong operator.Unfortunately, accidents still take place repeatedly.

SUMMARY OF THE INVENTION

The present invention is based on the technical problem of indicatingsafety devices to add on to stair-climbing systems in danger of tiltingover.

This technical problem is solved by safety devices.

These safety devices, for which there are the designs and furtherdevelopments defined, have numerous advantages.

A first advantage quite substantial for the interested parties is thatthey can be added on to all known stair-climbing systems, includingstair-climbers for conveying wheelchairs with handicapped persons, andthose yet to be developed, in such a way that falls will no longer bepossible in the future.

A further advantage is that the support arm can be constructedrelatively short, because it only needs to bridge over one to twostairs. Since it is also very narrow, tightly winding stairways do notpose any problems either.

As a third advantage, it should be cited that the support arms accordingto the invention do not in any way change the handling of thestair-climber system itself, because in the normal situation, they arefully movable relative to the stair-climber system. Only when thestair-climber system assumes a position where there is danger of tiltingover is the hinge of the support arm blocked, namely until the operatorhas brought the stair-climber system back into a safe position.

According to a first, preferred design of the invention, devices mountedin the lower end area of the support arm and preferably made of anelastic and thus stairway-protecting material bring about a supportaction impacting largely vertically on the stepping surface of the nextstep down and the step below that. It has been shown that the support onthe stepping surface of the stairs is much safer and more reliable thana support at the front edge of the steps. The jolt caused when the hingeis blocked is optimally intercepted.

At the free end of the support arm, numerous of support feet arepreferably mounted or molded on, one of which supports itself on thestepping surface of the next step down or the step below that in case ofdanger, as already mentioned. The arrangement of several support feetmakes possible an optimal adaptation to different heights and depths ofthe stairs.

According to a further development, the support feet are divided intotwo units. One unit, preferably the upper one, is mounted sliding andpivoting on the support arm against a spring and is equipped with ablocking system that blocks the movable unit as soon as the forcebrought to bear on the stairway overcomes the force of the spring, whichis always the case when the stair-climber is in danger of falling overthe stairway and the braking and blocking system has blocked the hingeof the support arm.

In particular in order to protect the stair edges, according to anadvantageous further development of this invention it is recommended tomount a runner parallel to the support arm, wherein a draw spring pullsthe support arm into the runner in such a way that in the normalsituation, only the front edge of the runner rests on the stair edges.It is understood that the spring force must be measured in such a waythat in case of danger, the support feet of the support arm can deploytheir support function without delay.

The runner preferably has a U-shaped cross-section. In this way, in thenormal situation the support arm and its support feet are covered on allsides.

In order to protect the stair edges, the front edge of the runner can becoated with an easily sliding material. An even better protectionresults when a continuous belt is mounted in front of the front edge ofthe runner.

As was already mentioned, the hinge of the support arm must be blockedas immediately as possible as soon as the stair-climber leansdangerously forward and threatens to fall down the stairway. That meansthat the angle of the stair-climber must always be measured andmonitored.

For this purpose, a heeling sensor is preferably used, in the form of apendulum mounted on the stair-climber or on the mounting system.

Several variants are possible for the system for blocking the hinge.

According to a first variant, the braking and blocking system consistsof a ratchet wheel and a ratchet. In this connection, the center of theratchet wheel is preferably situated in the center of the axis ofrotation. The ratchet is designed as a pendulum and mounted swingingaround its own axis on the mounting system. As soon as the stair-climbertips forward, the ratchet engages the teeth of the ratchet wheel andblocks the hinge. Such a blocking system is mechanically simple andfunctionally reliable.

According to a variant thereof, the center of the ratchet wheel isoffset relative to the axis of rotation. The ratchet is mountedswiveling around its own axis on the mounting system and is held in itshome position defined by a spring between the ratchet and the mountingsystem. This variant of construction has the advantage that the ratchetdoes not have to adjust itself due to gravity, thus allowing greaterfreedom in construction. Also, the function corresponds to that of thefirst variant.

In both variants, the ratchet advantageously consists of a low-mass partthat quickly engages the ratchet wheel due to its low mass, and ahigh-mass part that is responsible for maintaining the verticaldirection. Both parts are drawn together by a spring that is weakenough, however, that the ratchet's rapid engaging of the ratchet wheelis not delayed.

In both forms of construction, the angle of the ratchet wheel relativeto the support arm is advantageously adjustable. In this way, shiftingof the overall center of gravity, caused by different dimensions andweights of the stair-climber, the wheelchair and the handicapped person,can be compensated.

An alternative form of construction for the braking and blocking systemis a lockable tension bar of finite length between the support arm andthe mounting system or stair-climber.

A shoe brake can also be used as an alternative to this.

A spring band belt brake is preferred, because it works very quickly andreliably and has the necessary free-wheeling function.

As an alternative, an electric coupling can also be used.

According to a further variant, the braking and blocking system isdesigned as a lockable cylinder piston unit. These are preferablycylinder piston units with an internal fluid circuit and a checkvalve—controlled by the heeling sensor—in the fluid circuit. Hydraulicoils as well as gases come into consideration as the fluid.

According to an advantageous further development of the invention, thereis a support spring between the support arm and the mounting plate. Thissupport spring must be designed in such a way that it is powerless whenthe stair-climber system is in the properly inclined position relativeto the stairway. If the stair-climber leans backward toward thestairway, the spring presses it back into the normal position. If thestair-climber is tending to tilt dangerously forward, the spring pullsit back into the proper position. In both cases, the support spring thusrelieves the operator in terms of strength.

If the support arm is equipped with a runner, the springs between thesupport arm and the runner as well as between the support arm and themounting system are to be coordinated in terms of force in such a waythat if the stair-climber equipment leans dangerously down the stairs,the runner recedes and thereby releases the support feet to posethemselves on the stair.

To relieve the operator even more and also be able to convey heavy loadsquickly and, above all, safely over the stairs, a drive is providedparallel to the braking and blocking system. This can be an electricmotor with a screw thread, a hydraulic cylinder or the like. In anycase, the drive is controlled dependent upon the difference between thedesired position and actual position of the support arm relative to thestair-climber and/or the pressure force of the support arm on thestairway.

To support the support arm on the stepping surface of the stairs, notonly support feet are suitable but also, for example, a continuouscreeper band. Support wheels that are attached to a two-or three-armturnstile are also suitable. Constructions of the turnstile and supportwheels are already used in stair-climber systems. Lastly, there is eventhe possibility to equip the safety device with a power-driven drivethat actively supports the lift mechanism of the stair-climber and ismounted on the support arm.

According to a first variant thereof, the creeper band or the turnstilewith the support wheels can be driven by a motor. According to a secondvariant, a paternoster-type lift mechanism can also be provided on thesupport arm.

The lift mechanisms on the stair-climber and on the support arm arepreferably synchronized with each other. In this case, the wheelchair isconveyed up and down the stairs with only minimal vibration. Theoperator has essentially only a guiding function then, and no longer aholding function. Such stair-climbers can thus also be operated bypersons with less strength. However, the braking and blocking systemremains active in these cases as well and in case of danger, preventsthe stair-climber with the wheelchair and handicapped person fromtipping over the stairway.

BRIEF DESCRIPTION OF THE INVENTION

With the help of the drawings, the invention will be explained in moredetail in the form of an example of execution. They show:

FIG. 1 in schematic diagram, the side view of a stair-climber with awheelchair on a stairway,

FIG. 2 a view of a section of the stair-climber of FIG. 1 with a firstsafety device,

FIG. 3 in cutout form, the stair-climber of FIGS. 1 and 2 with amodified safety device,

FIG. 4 a section of the stair-climber of FIG. 1 with a third safetydevice,

FIG. 5 a schematic side view of a stair-climber with wheelchair and afourth form of construction of a safety device and

FIG. 6 a schematic side view of a stair-climber with wheelchair and afifth form of construction of a safety device.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows in a schematic side view a stair-climber system 10 standingon a stairway 1 with a wheelchair 9 attached. The stair-climber system10 stands with its wheels 12 on a stair. In this case, as an example, apaternoster-like mechanism 13 is illustrated as the lift mechanism forconveying the wheelchair 9 up and down the stairs. In principal,however, all types of comparable lift mechanisms as described in theintroductory description are suitable. Handles 14 on an operating rod 11enable the operator to lean the stair-climber 10, the wheelchair 9 andthe handicapped person far enough backwards that the overall center ofgravity S of this combination is situated exactly above the axis of thewheels 12, to keep the combination in this position and guide it up anddown the stairs.

As soon as the lift mechanism 13 is activated, the wheels 12 losecontact with the stairway 1. In this way, the center of gravity S is nowsituated in front of the bearing of the stair-climber 10 on the stairway1. The stair-climber 10, the wheelchair 9 and the handicapped person arein danger of falling forward over the stairway 1. The operator mustprevent this by pulling on the handles 14 with appropriate forcefulness.Practical experience has unfortunately proven that this is not alwayspossible.

FIG. 2 shows in a schematic, partly broken view, a safety deviceattached to the stair-climber system 10. The safety device's task is toprevent the combination of the stair-climber system 10, the wheelchairand the handicapped person from falling down the stairs if the center ofgravity S shifts too far forward.

The safety device first of all comprises a mounting system 20 that isattached to the stair-climber climber 10. The attachment part 22 of themounting system 20 can be easily adapted to the respective stair-climberin such a way that the safety device can be added to all types ofstair-climbers.

Provided on the mounting system 20 is a horizontal hinge pin 21 on whicha support arm 30 is mounted freely rotating. The support arm 30 extendsover very few, e.g. one or two stairs 1. At its free end, it is equippedwith numerous of non-skid support feet 31 that are mounted on a strut 39in such a way that in case in danger, they are supported nearlyvertically on the stepping surface of a stair 1.

While the support arm 30 must be fully movable relative to the mountingsystem 20 or the stair-climber system 10 in the normal situation, incase of danger it must be immediately blocked. A braking and blockingsystem 40 is used for this purpose. In the present example, thisconsists of a ratchet wheel 32 and a ratchet 41, 42. The ratchet wheel32 is attached to the support arm 30, in connection with which the anglebetween the ratchet wheel 32 and the support arm 30 can be adjusted ifnecessary. Bores 34 are provided for this purpose.

The ratchet 41, 42 is suspended freely hanging from the mounting system20 around a horizontal axle 44. As long as the stair-climber system 10is properly inclined rearward, the ratchet wheel 32 and the ratchet 41,42 are at a certain distance from each other. As soon as thestair-climber system 10 straightens up, the distance between the ratchet41 and the ratchet wheel 32 shortens according to a sinus function untilthe ratchet 41 finally engages the teeth 33 of the ratchet wheel 32. Inthis way, the support arm 30 is blocked and the stair-climber system 10cannot straighten up further. If the operator leans the stair-climbersystem 10 properly rearward again, the ratchet 41 is released from theratchet wheel 32 and the support arm 30 is able to move freely.

As FIG. 2 shows, the ratchet consists of a first, light part 41 that hasthe ratchet tooth, and a second, heavy part 42 that is responsible forthe constant vertical position due to gravity. Both parts 41, 42 areconnected via a light spring 43. Due to this two-part construction, theratchet tooth on the light ratchet part 41 can very quickly engage theratchet wheel teeth 33.

A runner 50 with U-shaped cross-section is inverted via the support arm30 and the support feet 31. A draw spring 52 pulls the support arm 30into the runner 50. The front surface 51 of the runner 50 is shaped insuch a way that the support feet 31 disappear behind the front surface51 in the normal situation. In this way, only the front surface 51slides on the stair edges. If the front edge 51 is coated with an easilysliding material, the stair edges are protected

The draw spring 52 is weak enough, however, to ensure that in case ofdanger, the support feet 31 can brace themselves without delay—sittinglargely vertically—on the stepping surface of the next stair 1.

FIG. 3 shows a second form of construction of a safety device 40′ on thestair-climber 10. The ratchet engaging the teeth 33 of the ratchet wheel32 is once again in two parts 41′, 42′, that are connected by a weakspring 43; but in the present case only the heavy ratchet part 42′ ismounted suspended, while the light ratchet part 41′ is standing. Thefunction of the ratchet 41′, 42′ otherwise corresponds to the functionof the ratchet 41, 42 in FIG. 2.

An additional support spring 60 is provided between the mounting system20 and the support arm 30. It is sized in such a way that it ispowerless when the stair-climber 10 is in the properly inclined positionrelative to the stairway 1. If the stair-climber 10 changes its positionforward or rearward, the support spring 60 pulls or presses thestair-climber 10 back into the proper position.

The forces are transmitted via the support arm 30 and the runner 50 ontothe respective stair. In this way, the operator is relieved of thestair-climber 10.

In order not to lose the receding function of the runner 50, 51 in caseof more pronounced, dangerous leaning of the stair-climber 10 downward,the two springs 52, 60 must be coordinated in terms of force.

FIG. 4 shows a third form of construction of a safety device on thestair-climber 10. A lockable cylinder piston unit 48 with internal fluidcircuit and an electrically controllable check valve 49 in the fluidcircuit is provided as the braking and blocking system 40″ between themounting system 20 and the support arm 30. The position of thestair-climber 10 on the stairway 1 is measured by means of anelectromechanical heeling sensor 70 that transmits a blocking signal tothe check valve 49 when the stair-climber 10 assumes a dangerousposition.

As a modification of the forms of construction of FIGS. 2 and 3, in thepresent example of construction the strut on which the support feet 31are situated is designed in two parts. One strut part, the lower unit39.1, is rigidly attached to the support arm 30. On the other hand, thesecond strut part, the upper unit 39.2, is mounted able to slide andswivel relative to the support arm 30. In a further development, ablocking system 36 is provided to block the upper unit 39.2 in the eventthe stair-climber 10 is in danger of falling over the stairway and whenthe braking and blocking system 40 has blocked the hinge of the supportarm 30. A combination 37 of a stud and an elongated hole in connectionwith a pressure spring 38 is used to effect the sliding and swiveling ofthe upper unit 39.2.

Thanks to such a two-part design of the strut 39.1, 39.2, the safetydevice is also suitable for extremely flat stairways 1.

FIG. 5 shows an active safety device. For this, the support arm 30 isequipped with a motor-driven lift system 130 that corresponds to thelift mechanism 13 of the stair-climber 10. A jockey roller 131 and atouch sensor 132 are used as control and safety switch for the liftsystem 130. When the lift mechanism 13 on the stair-climber 10 isproperly coordinated with the lift system 130 on the support arm 30, thetwo lift mechanisms run synchronously and the wheelchair 9 with thehandicapped person is conveyed up and down the stairs practicallywithout any function-related tilting movements of the wheelchair 9.Owing to the braking and blocking system still present, however, in thiscase as well the support arm 30 is immediately blocked if thestair-climber 10 straightens up dangerously and threatens to fall overthe stairway 1. It is understood that in such a case, the liftmechanisms 13, 130 are immediately stopped.

FIG. 6 shows a safety device that can be designed passive as well asactive. At the free end of the support arm 30, a three-arm turnstile 230is attached rotating and has three support wheels 231. The supportwheels 231 are supported on the stepping surface of the stairs. If theturnstile 230 is motor-driven and the rotational speed is synchronizedwith the lift drive 13, the wheelchair 9 is conveyed up and down thestairs problem-free and practically without vibrations once again.

In addition, as FIGS. 5 and 6 show, the support arm 30 with the attacheddevices and mechanisms can be swung under the wheelchair 9 if thewheelchair 9 is driven or pushed on level surfaces.

What is claimed is:
 1. A safety device to be used with stair-climbersystems for conveying equipment and goods, and adapted for use withwheelchairs with handicapped persons, comprising: a mounting system forattaching to the stair-climber system or to the wheelchair; a hinge pinhingedly attached to the mounting system; a support arm rotatablymounted on the hinge pin and adapted to extend below said wheel chair orstair climber; a braking and blocking system attached to the support armon one end and to said mounting system on an end thereof; and a sensorfor determining an angle of inclination of the stair-climber in order tocontrol the braking and blocking system to block the support arm whenthe stair-climber and the wheelchair begin to tip over when ascending ordescending a stairway, and release the support arm when thestair-climber and wheelchair are inclined properly relative to thestairway.
 2. The safety device according to claim 1, further comprising:devices attached in a lower end area of the support arm which bringabout a support action impacting substantially vertically on a steppingsurface of a next stair down or on a stair below the next step down. 3.The safety device according to claim 1, further comprising: at least twosupport feet mounted or molded on a free end of the support arm, one ofthe at least two support feet supports itself on the stepping surface ofa step when the stair-climber and wheelchair begin to tip over.
 4. Thesafety device according to claim 3 wherein: the support feet are dividedinto a lower unit and an upper unit, wherein: the upper unit is mountedsliding and pivoting on the support arm against a spring; and a blockingsystem blocks the upper unit as soon as a force brought to bear on thestairway as overcome the force of the spring.
 5. The safety deviceaccording to claim 4, wherein the blocking device includes: a pin on thesupport arm; an elongated hole on the movable unit; teeth on the supportarm; and a tooth on the movable unit.
 6. The safety device according toclaim 3 wherein: the support feet are divided into two units, wherein:one unit of the two is mounted sliding and pivoting on the support armagainst a spring; and a blocking system blocks the one unit as soon as aforce brought to bear on the stairway has overcome the force of thespring.
 7. The safety device according to claim 1, further comprising: arunner mounted parallel to the support arm; and a tension spring pullingthe support arm into the runner in such a way that when thestair-climber is inclined properly relative to the stairway only a frontedge of the runner rests on the edges of the stairs.
 8. The safetydevice according to claim 7, wherein the runner has a U-shapedcross-section.
 9. The safety device according to claim 7, wherein thefront edge of the runner is coated with a sliding material.
 10. Thesafety device according to claim 1, wherein the sensor is a pendulummounted on the stair-climber or on the mounting system.
 11. The safetydevice according to claim 1, wherein the braking and blocking systemincludes: a ratchet wheel; and a ratchet which engages said ratchetwheel.
 12. The safety device according to claim 11, wherein a center ofthe ratchet wheel is situated in a center of the hinge pin, and theratchet is designed as a pendulum and is mounted swinging on themounting system around an axle.
 13. The safety device according to claim12, wherein the ratchet includes a low-mass part and a high-mass part,and a spring pulls both the low mass part and the high mass parttogether.
 14. The safety device according to claim 11, wherein: thecenter of the ratchet wheel is offset relative to the hinge pin; theratchet is mounted swiveling on the mounting system around an axle; anda spring between the ratchet and the mounting system defines a homeposition of the ratchet.
 15. The safety device according to claim 11,wherein an angle of the ratchet wheel relative to the support arm isadjustable.
 16. The safety device according to claim 1, wherein thebraking and blocking system is a lockable tension bar of finite lengthbetween the support arm and the mounting system or the stair-climber.17. The safety device according to claim 1, wherein the braking andblocking system is a shoe brake.
 18. The safety device according toclaim 1, wherein the braking and blocking system is a spring band brake.19. The safety device according to claim 1, wherein the braking andblocking system is an electric coupling.
 20. The safety device accordingto claim 1, wherein the braking and blocking system is a lockablecylinder piston unit.
 21. The safety device according to claim 20,wherein the lockable cylinder piston unit has an internal fluid circuitand a check valve controlled by the sensor in the fluid circuit.
 22. Thesafety device according to claim 1, further comprising a support springprovided parallel to the braking and blocking system, wherein thesupport spring is powerless when the stair-climber is properly inclinedrelative to the stairway.
 23. The safety device according to claim 22,further comprising: the support spring being weaker than a tensionspring which pulls the support arm in a first direction into a runner insuch a way that when the stair-climber is inclined uprightedly relativeto the stairway only a front edge of the runner rests on the edges ofthe stairs.
 24. The safety device according to claim 1, furthercomprising: a drive provided parallel to the braking and blockingsystem, wherein the drive is controlled by at least one of a differencebetween a desired and an actual position of the support arm relative tothe stair-climber and a pressure force of the support arm on thestairway.
 25. The safety device according to claim 24, wherein the driveand the braking and blocking system are integrated into a single unit.26. The safety device according to claim 1, further comprising acontinuous creeper band attached to the support arm.
 27. The safetydevice according to claim 26, wherein the continuous creeper band ismotor-driven.
 28. The safety device according to claim 1, wherein aturnstile with at least two support wheels is attached at a free end ofthe support arm.
 29. The safety device according to claim 28, whereinthe turnstile is motor-driven.
 30. The safety device according to claim29, wherein the motor-driven turnstile is synchronized with a liftmechanism of the stair-climber.
 31. The safety device according to claim1, further comprising a paternoster lift mechanism attached to a freeend of the support arm.
 32. The safety device according to according toclaim 1, wherein: the support arm is pivotally attached so as to befreely rotating on the hinge pin, and the hinge pin is rigidly attachedto the mounting system.